Any active domain that is added in a hosting account includes a number of records that permit it to perform properly. In the standard case, the name servers (NS records) show where the Internet domain is hosted and they are set on the side of the registrar company, but on the lower level there are certain records set through the hosting company like A (IP address of the website/server), MX (e-mail server), SRV (using a domain for non-website purposes on a particular port number such as Voice-over-IP), and so on. With access to these records and by having the ability to edit them, you can have your web site with company A and your e-mail messages with company B, for instance. This offers you more independence since you can choose the best provider for every one of these services and you don't have to stick to only one company. After you pick a hosting company, you have to make certain that you have access to all DNS records freely since some providers have an extra fee for this feature.